The present invention relates generally to determining the location of a mobile device within a wireless network, and more particularly, to determining the location of a mobile device within a wireless network with a single access point and with adequate accuracy for a home environment.
In recent years, businesses in most all industries have improved their productivity by linking their computer systems via a local area network and/or wide area network and installing software systems to track and manage the status of the business""s operations, This has enabled businesses to automate many tasks that were traditionally performed using manual paper based systems. The network infrastructure employed in such systems typically includes a cabled backbone communicating data between various computing systems utilizing a protocol such as Ethernet. Additionally, wireless access points are coupled to the cabled backbone and are used to communicate data to portable computing systems which are within a zone, or cell, around the access point in which a portable computing system and the access point can effectively communicate data. The physical topology of the cabled backbone and placement of each wireless access point will typically provide for cell coverage throughout most geographic areas of the facility.
More recently, it has been desirable to provide systems for locating portable computing systems within the facility for purposes of tracking movement of goods and/or personnel throughout the facility. U.S. Pat. No. 5,519,760 to Borkowski et al. discloses a cellular position locating system which teaches a method for determining which, of a plurality of cells of a cellular telephone network, a mobile device is located within. More recently, U.S. Pat. No. 6,006,096 to Trompower discloses a system for measuring the strength of a transmitted signal from a mobile device at a plurality of wireless access points to calculate a more specific location of a mobile computing device.
In the consumer market, it has been contemplated to use the existing plain old telephone service (POTS) network in homes for communicating data between various computing devices. More specifically, the Home Phone line Network Association (HPNA), which is an industry consortium of companies including Advanced Micro Devices of Sunnyvale California, has proposed standards for communicating data on the POTS network. With the advent of HPNA systems it is possible for consumers to utilize the existing POTS infrastructure in their homes to network several computing devices in a similar manner to the way an Ethernet network infrastructure interconnects computers in a commercial facility, although at a slower data rate. It has also been envisioned to couple a wireless access point to the POTS network which would serve to couple data between devices on the POTS network and mobile computing devices utilized within the home. Because the range of wireless communications typically exceeds the physical size of most homes, only a single access point would be required to support wireless communications throughout the entire home. As such, home wireless access systems do not need to include multiple cell roaming and registration systems as are required by most commercial systems.
A problem associated with a single cell system is that the mobile device location systems taught in both Borkowski and Trompower would not work because both require use of more than one access point. Additionally such systems, and even more expensive systems such a global positioning systems (GPS), locate a device within a range that is too large compared to the size of a typical home to be useful. For example, if such a system were to locate a device within three meters of accuracy, that information could not be used effectively to determine which room or even on which floor a mobile computing device is located.
Therefore, what is needed is an inexpensive system for locating a mobile device within a home wireless networking environment and locating the device with an accuracy commensurate with the size of a typical home environment.
A first aspect of this invention is to provide a system for locating a mobile device within a wireless network environment. The system comprises an access point for wirelessly receiving a data frame from the mobile device and forwarding the data frame to a location monitoring appliance on a wired network backbone. A plurality of location beacons each transmit a unique beacon signal, which may be modulated illumination, which represents the location of the beacon. The mobile device includes a beacon detection circuit for detecting the modulated illumination beacon signal, a frame selection circuit for selecting one of a plurality of predetermined data frames for transmission in response to the beacon signal, and a transmission circuit for transmitting the selected data frame to the location monitoring appliance. The location monitoring appliance provides data to an operator which is representative of the mobile device and the beacon signal received by the mobile device.
Each of the predetermined data frames represents a predetermined message and is compliant with the network protocol. The frame selection circuit receives the signal from the beacon detection circuit and selects the predetermined data frame which includes the predetermined message associated therewith. Each data frame may includes a series of transmission signal values which represent a network address of the location monitoring appliance (e.g. destination address), a network address of the mobile device (e.g. source address), a network protocol compliant preamble, and the predetermined message. In the exemplary embodiment, the series of transmission signal values represent a baseband transmission signal and the transmitter includes a D/A converter for generating an analog baseband signal and an analog mixer for generating the modulated carrier.
The location monitoring appliance may activate at least one of an audio and visual alarm based on the network address of the mobile device and the predetermined message matching an alarm condition. The alarm may be activated on a computing device by sending a signal to the mobile computing device via the wireless network.
A second aspect of the present invention is to provide a network device for reporting its location within a wireless network to a remote computing device. The network device comprises: a) a location detection circuit for receiving a modulated illumination beacon signal from one of a plurality of location beacons, each of which transmits a unique modulated illumination beacon signal; b) a memory storing a plurality of sets of transmission signal values representing a transmission frame of a predetermined message complying with a predetermined network protocol, each set of transmission signal values being associated with one of the plurality of beacon signals; c) a transmission selection circuit for selecting the set of transmission signal values associated with the received beacon signal; and d) a transmitter coupled to the memory generating a modulated carrier signal representing the selected set of transmission signal values.
The transmission signal values may represent a network address of the remote computing device, a network address of the network device, a network protocol compliant preamble, and message data. Preferably, the transmission signal values represent a baseband transmission signal and the transmitter includes a D/A converter for generating an analog baseband signal and an analog mixer for generating the modulated carrier.
The remote computing device may activate at least one of an audio and visual alarm based on the network address of the network device and the predetermined message matching an alarm condition. The alarm may be activated on a computing device by sending a signal to the mobile computing device via the wireless network.
A third aspect of the present invention is to provide a method of reporting a location of a network device to a remote computing device. The method comprises: a) receiving a modulated illumination beacon signal from one of a plurality of location beacons; b) selecting a transmission frame corresponding to the received beacon signal from a plurality of transmission frames pre-stored in a memory; and c) transmitting the selected transmission frame to the remote computing device.
The pre-stored transmission frame may include a sequence of transmission signal values representing a network address of the remote computing device, a network address of the network device, a network protocol compliant preamble, and message data. The transmission signal values may represent a baseband transmission signal and the step of transmitting the selected transmission frame may include converting the signal values to an analog baseband signal and mixing the analog baseband signal up to carrier frequency.
The method may further include generating at least one of an audio and visual alarm based on the network address of the network device and the predetermined message matching an alarm condition. The alarm may be activated on a mobile computing device by sending a signal to the mobile computing device via the wireless network.